Improvement of the High-Temperature Erosion-Corrosion Resistance of Incoloy 800 by Cladding of 25.35.4CNB Reinforced by SiC
The objective of this study is to improve the high-temperature erosion-corrosion resistance Incoloy 800 for the application used as thermowell at 900°C. In weld cladding procedure, silicon carbide (SiC) particles were pre-deposited on the Incoloy 800 substrate, followed by the cladding of Ni-base alloy filler (34Ni-25Cr-0.4C-Ti-W-Mo) by a gas tungsten arc welding. A theoretical amount of SiC particles mixed with filler was 2 - 30%wt. A particle size of SiC was in the range of 50-150 mm. The results showed that the addition of 15%wt SiC led to the maximum hardness of the cladding layer. Addition of particles more than 15wt% tended to provoke cracks in cladding layer. The larger particle size exhibited the higher hardness. An erosion rate of cladding surface was further tested by the perpendicular impingement of 1-mm SiC abrasion sands on the sample surface with air flow velocity of 220 m s-1 at 900°C in air. For cladding layer with the same amount of SiC mixed, the one mixed with larger particle size exhibited the higher erosion-corrosion resistance. Likewise, for cladding layer mixed by the same size of SiC, the addition of particle with a smaller amount promoted the higher erosion-corrosion resistance. The addition of 2.6 wt% SiC particles with 150 mm size in cladding layer showed the surface with the best erosion-corrosion resistance in this study. No oxide scale was, however, observed on eroded surface due to the spallation by high impact erodent particles.
Toshio Maruyama, Masayuki Yoshiba, Kazuya Kurokawa, Yuuzou Kawahara and Nobuo Otsuka
P. Promdirek et al., "Improvement of the High-Temperature Erosion-Corrosion Resistance of Incoloy 800 by Cladding of 25.35.4CNB Reinforced by SiC", Materials Science Forum, Vol. 696, pp. 242-247, 2011